One of the most basic and essential martial arts techniques is the proper execution of what is known as a low kick. That is, a low kick by the martial artist is to the lower extremity of the leg of an opponent, usually the forward leg. In principle, this blow is easily taught and demonstrated but in application and execution, subtleties are sometimes difficult to master without practice on a human leg. The primary purpose of such a blow to a human leg is to discourage further attack and, if necessary, to break the leg at the knee. A properly executed blow can cause severe permanent damage to the human leg and is therefore commonly avoided in practice situations.
The alternative then is to aim kicks at a non human leg is order that no one be hurt. The disadvantage, however, is that upon being kicked, presently available non human leg substitutes do not respond as a human leg would respond and the trainee misses important subtleties in the execution and delivery of the low kick.
Various devices are known in the martial arts field employing spring loaded appendages but none of these have been found suitable for training in the execution of low kicks. No known devices permit a humanlike "breakage" response when kicked, while permitting return of the leg to a practice position for reuse.